1. Field of Invention
This invention relates generally to discharge valves for managing urinary incontinence and retention, preferably discharge valves associated with intra-urethral or "indwelling" Foley-type urinary catheters, the valve being an externally preferably located multi-axial palpitatable discharge valve and having protective shoulders to minimize inadvertent placement of force on the valve which is sufficient to unintentionally open the valve and release retained urine.
2. Prior Art
The field of urinary catheters has long been dominated by the Foley-type catheter, which is well known in the art and comprises an inflatable balloon for disposition within a patient's bladder and a discharge or drainage tube which extends from the bladder, through the urethra, to the exterior when the catheter is in place within the patient. The Foley-type catheter provides passive urinary drainage, and the ability to clamp the catheter closed at a location exterior of the patient. Representative examples of Foley-type catheters are shown in U.S. Pat. Nos. 4,055,187; 4,154,243; 4,188,954; and 4,335,723 to Patel.
Foley-type catheters have many drawbacks. These drawbacks include, among other things, relatively high intra-urethral leakage rates, the inability to selectively control discharge, and the diminution in the patient's mobility or physical activities due to the constant need for a drainage collection device interconnected to the open catheter.
Many attempts have been directed towards solving these problems, and the prior art reflects that many basic improvements have been adopted and combined in a variety of forms to optimize the function of the particular catheters. However, practical, reliable, and commercially viable alternatives are still needed.
One alternative provides a releasable connection between the Foley-type catheter and the external drainage tube to enhance mobility, as shown in U.S. Pat. No. 4,955,858 to Drews. A check valve can also be disposed at a point along the catheter or drainage tube as shown in U.S. Pat. No. 3,967,645 to Gregory. However, these improvements do not address other problems such as an intra-urethral leakage, and have not resulted in a solution that is satisfactory for most patients.
The use of an inflatable balloon or other blocking device to minimize intra-urethral leakage around the exterior of the catheter, and valves disposed within the catheter body to permit selective voiding, are considered fundamental advances in the art. Early examples of developments along these lines include U.S. Pat. No. 3, 841,304 to Jones and U.S. Pat. No. 3,503,400 to Osthagen. A blocking device comprising a hydrogel collar disposed around the catheter tube of a Foley-type catheter is disclosed. The collar is designed to slide axially along the catheter tube into contact with the body at the distal end of the urethra to hold the balloon in sealing contact with the neck and orifice of the bladder. The collar also provides an additional obstacle to leakage at the distal end of the urethra.
Valves contained within catheters that can be manipulated by bending, flexing, or extending the catheter are shown in U.S. Pat. No. 4,822,333 to Lavareene; and U.S. Pat. Nos. 4,432,757 and 4,350,161 to Davis. These catheters are generally unsuitable for use by female patients, and are subject to leakage resulting from normal body movement when used in male patients.
Collapsible- or restricted-lumen catheters that have predetermined release pressure thresholds have also been disclosed. However, these catheters are subject to leakage, do not drain completely, and have predetermined operational pressure ranges which may not be appropriate for a large number of patients without undue experimentation particularly when determining a safe high end limit to the range. In addition, the relatively short distance between the orifice of the bladder and the distal end of the urethra in female patients limits the suitability of some designs that require an extended length of lumen to maintain the requisite pressure threshold. Representative examples of such designs are shown in U.S. Pat. No. 4,553,959 to Hickey and U.S. Pat. No. 3,672,372 to Heimlich.
U.S. Pat. No. 5,234,409 to Goldberg; U.S. Pat. No. 5,114,398 to Trick; and U.S. Pat. No. 5,030,199 to Barwick show representative examples of valved catheters designed for female patients. These catheters incorporate a variety of valves and actuators which illustrate some of the inherent obstacles in designing catheters for female patients, namely providing a manipulable or palpitatable valve that can be located and gripped by the patient without presenting a hygienic risk or being inconvenient for the patient to operate.
Intra-urethral plug-type devices have also been disclosed. These devices include palpitatable or manually activated valves for selective control over voiding. They are generally retained within the distal end of the patient's urethra using inflatable bulbs, radial serrations, or regions of enlarged diameter, and generally include an exposed portion that permits selective activation of the valve or periodic removal of the device. Representative examples of such devices are shown in U.S. Pat. No. 5,131,906 to Chen; U.S. Pat. No. 5,090,424 to Simon; U.S. Pat. No. 4,968,294 to Salama; U.S. Pat. No. 4,457,299 to Cornwall; and U.S. Pat. No. 3,768,102 to Kwan-Gett.
A wide variety of discharge valve designs have been contemplated for use with urinary catheters. These valves are usually actuated mechanically, but may also be actuated magnetically or by other means. The more prevalent types of mechanical valves include ball-and-seat, duckbill, inflatable check, plug, and dome-type valves. These valves may all be operated manually by the patient, however, some types of valves are identified as "palpitatable" based upon a portion of the valve being squeezed or pressed in order to open the valve. The palpitatable valve may be disposed internally or externally for male patients, although internal valves may be more difficult to use, uncomfortable, and unreliable. The palpitatable valve must be located externally for a female patient. Palpitatable discharge valves may also be classified as orientation-dependent (uniaxial) or orientation-independent (multi-axial), based upon whether pressure must be applied to a pair of selected points or surfaces in order to open the valve sufficiently for normal discharge operation, or whether the valve will open when pressure is exerted radially from any two opposing directions.
These basic types of mechanical, inflatable, and palpitatable valve configurations are displayed in U.S. Pat. No. 5,306,226 to Salama; U.S. Pat. Nos. 5,269,770 and 5,261,896 to Conway; U.S. Pat. Nos. 4,946,449 to Davis; U.S. Pat. No. 4,932,938 to Goldberg; U.S. Pat. No. 4,846,784 and 4,813,935 to Haber; and U.S. Pat. No. 4,643,169 to Kross, as well as several other references previously discussed. Representative examples of magnetically-actuated valves are shown in U.S. Pat. No. 5,041,092 to Barwick and U.S. Pat. No. 4,731,670 to Loe.
The Davis '449, Goldberg '938, and Haber '794 patents disclose several types of palpitatable valves that may be disposed internally or externally. A uniaxial duckbill valve may be rotated between the user's fingers until pressure is directed on the proper sites to maximize fluid flow, but the rotational torque can cause irritation, inflammation, and leakage. The Goldberg '938 patent teaches a tactile sensing means for determining the proper orientation of a duckbill valve to ensure complete opening, however properly orienting the catheter and valve upon initial insertion still requires time and training. In addition, the Davis '449 and Goldberg '938 patents both disclose dome-type valves that operate substantially the same as uniaxial duckbill valves. These dome-type valves similarly provide two opposing valve elements, but the slit or cut forming the valve opening approaches or intersects the side wall of the valve at a point below or downstream of the apex of the dome. While this configuration provides enhanced drainage capabilities for small aliquots of fluid remaining within the valve body compared with conventional duckbill valves, the proximity of the ends of the slit to the side wall of the catheter body restricts the amount that the valve can be opened in the region nearest the side wall (and therefore the lowest or most downstream portion of the valve) and risks nicking or scoring the side wall of the valve when the slit is cut. One alternative shown in the Davis '449 patent appears as a separate dome-shaped valve piece that is cut and inserted within the catheter body, which does not eliminate the restriction on the width of the valve opening adjacent the side wall of the valve body, and requires additional time, labor, costs, and quality control measures to accommodate the additional manufacturing steps.
The Davis '449 patent further shows a drainage tube connector being inserted through the dome-type valve to hold the valve in an open position. Similarly, U.S. Pat. No. 3,421,509 to Fiore discloses a protective sleeve for a urinary catheter having several overlapping wedge-shaped flap elements that are opened by insertion of a drainage tube connector.
The Haber '784 patent discloses another valve design similar in longitudinal cross section to a duckbill valve, wherein the valve elements are lobes having extended contact surfaces that present a central lumen when pressure is applied, rather than conventional blade-type elements that pivot apart when the valve is deformed.
The use of duckbill valves having pivotal blade elements or dome-type valves having single or cross-shaped slits are generally preferred for palpitatable valves. However, existing catheter designs having palpitatable valves do not provide as reliable a closure under normal pressures as is generally desired. In addition, the valves do not adequately drain small aliquots of urine from within the valve, thereby fostering a highly infectious environment located in close proximity to contamination from the outside environment and a pathway for ready transmission of bacteria infection to the bladder.
Another problem associated with palpitatable valves is that the slightest force inadvertently exerted on the right place or places can open the valve allowing urine to flow. For instance, force can be placed on an external valve if it is pressed between a patient's legs when their legs are crossed. If so, urine can be released and the patient can be embarrassed by the unintended failure of the catheter valve to retain the urine. Furthermore, many of the valves are difficult to operate and require much more force to operate that is easily mustered by some elderly patients. Therefore, providing a valve which requires a reduced amount of force from the patient to operate, at the time that protection is provided to help minimize inadvertent or unintended operation of the valve resulting in the unintended release of urine.
In view of the many shortcomings and patient dissatisfaction with existing designs for urinary discharge valves, Applicants have developed a preferred urinary discharge valve design intended to meet the needs and desires of the majority of male and female patients suffering from incontinence or urinary retention disorders.